Forced convection heat exchangers capable of being used in kilns

A kiln system for drying a charge of lumber, the kiln system comprising:

• a kiln chamber defining a chamber interior space for receiving the charge of lumber for drying;
• an air moving device for circulating air in the chamber interior space along a flow path;
• and
• a plurality of pipe banks positioned in the chamber interior space, wherein:
• each pipe bank comprises a plurality of finned pipes for having a heated medium flow interiorly therethrough, and each pipe bank is positioned in the flow path so that air circulated by the air moving device flows exteriorly across the finned pipes, whereby heat is transferred from the finned pipes to the air circulated by the air moving device,
• each finned pipe comprises an elongate portion having opposite ends and extending in a longitudinal direction between the opposite ends, with the longitudinal direction being at least generally perpendicular to the portion of the flow path that is proximate the finned pipe,
• the pipe banks are spaced apart from one another and arranged side by side with respect to one another so that at least a portion of the flow path extends between adjacent ones of the pipe banks,
• the minimum distance defined between the adjacent pipe banks is substantially greater than the minimum distance defined between adjacent finned pipes in the same pipe bank in an end elevation view of the elongate portions of the finned pipes, and
• for each pipe bank, its finned pipes are arranged at least generally in a line in the end elevation view, and the pipe bank is arranged and any minimum distance defined between adjacent finned pipes of the pipe bank is sufficiently small in the end elevation view
• so that the adjacent pipe banks function as guide vanes for contributing to the defining of a turn in the flow path, with the turn at least generally following the lines that are defined by the arrangement of the finned pipes in the end elevation view.